1. Field of the Invention
The present invention, in general relates to removing caffeine from a foodstuff and, more particularly, to a method for removing a portion of the caffeine from an aqueous solution, such as an extract of a vegetable material, for example; a coffee or a tea, by exposure of the aqueous solution to a molecularly imprinted polymer.
The deleterious effects of excessive caffeine consumption are only partially understood at present. However, what is known is sufficient to generally determine and conclude that caffeine is potentially detrimental when consumed in excess.
For certain individuals, even a small intake of caffeine increases certain health risks and they, therefore, are required to either limit or in some circumstances, entirely eliminate their intake of caffeine.
Methods for decaffeinating foodstuffs are generally well known. For example, decaffeinated coffees have long been on the market. However, there are a few significant problems inherent with currently known decaffeination processes.
First, the majority of these processes use toxic organic solvents as part of the decaffeination process. This is a fact not generally well advertised for obvious reasons. If it were well known, confidence in the use of such decaffeinated products would decline and their consumption would similarly decline.
This is because most people who consume decaffeinated foodstuffs and beverages in particular, do so for health-conscious reasons. The possibility that they may instead be consuming unknown amounts of other potentially harmful substances that are used in, or are a product of the decaffeination process, is not likely to well received by such health-conscious individuals.
Also, the efficacy of current decaffeination methods varies considerably with the method. While some are capable of removing substantial percentages of caffeine, other methods are not as effective.
Those methods that are effective tend to be broad based in their approach, removing a wide variety of organic compounds not intended to be removed from the foodstuff. This can have a deleterious effect upon the taste of the foodstuff by removing organic compounds that normally give the foodstuff its unique character and flavor.
Another well known problem inherent, as was briefly mentioned hereinabove with certain decaffeination processes, is that they may affect the taste of the foodstuff. While some gains have recently been made in this regard, most consumers feel that decaffeinated products taste worse, perhaps even far worse, than their caffeine containing counterparts. This problem is so acute that many consumers who are advised to drink decaffeinated coffee, for example, quit drinking coffee entirely rather than endure a taste which they feel is vastly inferior to that which they have previously experienced.
One of the reasons for this is that the chemicals used to decaffeinate the foodstuff may themselves have a taste of their own that lingers in various amounts thereby coloring the taste of the decaffeinated product. This is confirmed by many consumers who state that decaffeinated coffee, for example, has a xe2x80x9cchemical tastexe2x80x9d that is unappealing.
And as mentioned hereinabove, the non-specific removal of organic compounds from the foodstuff also tends to remove certain of the ingredients that provide it with a delicate or otherwise characteristic flavor. Therefore, after decaffeination has occurred, the taste appeal may no longer remain. Consequently, market share will inevitably be less with a poor tasting decaffeinated foodstuff, in particular with a coffee or tea, that it would if the taste were minimally affected or better yet, unaffected except for that caused directly by the removal of the caffeine.
Another concern is cost. Decaffeinated products can cost more than untreated products. This is due to the time and labor involved in the decaffeination process as well as to the cost of materials used, such as chemicals. It is, of course, desirable to lessen the cost to decaffeinate a product, thereby making it more affordable for the general public to consume.
There is another disadvantage that the consumer of decaffeinated beverages faces and that is limited range of selection. For example, a coffee drinker who does not restrict his or her caffeine intake may purchase a great many varieties of coffee beans or various combination blends of these beans at most coffee roasting houses. However, if he or she wishes to consume a decaffeinated coffee, only a very few selections are likely to be available.
Furthermore, the use of organic solvents to decaffeinate coffees and teas pose environmental hazards as well. A very large quantity of organic solvents are presently being used for decaffeination purposes. These organic solvents are pollutants that can adversely affect the aquifer or otherwise contaminate the ground, either as waste products or if carelessly handled. They also pose a substantial risk to employees.
Also, some of the other processes presently used to decaffeinate vegetable materials expend considerable quantities of energy as the vegetable materials are repeatedly exposed to steam, For example.
While the deleterious environmental impacts from organic solvents and energy consumption may, at first seem insignificant, they are substantial once the true magnitude is understood. The quantity is so large that, literally, mountains of coffees are decaffeinated annually and the quantities of organic solvents that are used and eventually released into the environment as pollutants are enormous as is the energy that is consumed. Therefore, from the environmental perspective a process for decaffeinating aqueous solutions that conserves energy and substantially lessens the use of organic solvents is desirable.
Accordingly, there exists today a need for a method and product for decaffeinating an aqueous solution, such as an extract of a vegetable foodstuff that is safe to use, does not introduce new and potentially unpleasant tastes, can be used with a variety of beverages that contain caffeine, and is effective. Clearly, such a method would be useful and especially desirable.
2. Description of Prior Art
Decaffeination methods and devices for decaffeinating coffee are, in general, known. For example, the following patents describe various types of these devices:
U.S. Pat. No. 4,465,699 to Pagliaro, Aug. 14, 1984; and
U.S. Pat. No. 4,922,812 to Schweinfurth, May 8, 1990.
Methods involving molecular imprinting to form synthetic enzymes and synthetic antibodies are also, in general, known. For example the following patents describe various types of these devices:
U.S. Pat. No. 4,111,863 to Wulff, Sep. 5, 1978; and
U.S. Pat. No. 5,110,833 to Mosbach, May 5, 1992.
While the structural arrangements of the above described devices and methods, at first appearance, have similarities with the present invention, they differ in material respects. These differences, which will be described in more detail hereinafter, are essential for the effective use of the invention and which admit of the advantages that are not available with the prior devices and methods.
It is an object of the present invention to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that is effective at removing a portion of the caffeine from the aqueous extract.
It is also an important object of the invention to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that is economical to use.
Another object of the invention is to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that does not introduce unpleasant tastes to the extract.
Still another object of the invention is to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that is highly selective in removing the caffeine molecule while leaving unaffected other organic molecules.
Still yet another object of the invention is to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that does not expose the extract to substantial amounts of organic solvents or other undesirable or toxic chemicals.
Yet another important object of the invention is to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that is safe to use.
Still yet another important object of the invention is to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that is effective for use with coffees and teas.
Still yet another further important object of the invention is to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that is effective for commercial use.
Still yet another further especially important object of the invention is to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that is effective for consumer use.
Still one other object of the invention is to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that provides a method for containing the molecularly imprinted polymers useful in decaffeinating the aqueous extract.
Still one other important object of the invention is to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that provides an enclosure for containing the molecularly imprinted polymers adapted to permit the aqueous extract to flow through.
Yet one more useful object of the invention is to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that increases the variety of coffees and teas that are available in a decaffeinated form to consumers.
Yet one more especially useful object of the invention is to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that increases the variety of beverages available to a consumer that can be decaffeinated.
Yet one most useful object of the invention is to provide a method and product for decaffeinating an aqueous solution, such as an extract from vegetable material, using molecularly imprinted polymers that permits a consumer to decaffeinate a beverage.
Briefly, a process in accordance with the principles of the present invention includes the formation of molecularly imprinted polymers (MIPS) that contain an imprint of the caffeine molecule. MIPS to caffeine may be formed, for example, by the addition of caffeine to a polymerization mixture (also known as a xe2x80x9creaction mixturexe2x80x9d). The caffeine dissolves in the mixture and mixes with the monomers. Polymerization is then initiated by one (or more) of several possible methods, but typically involves irradiation of the cooled mixture with ultra violet light. However, heating the mixture and/or adding a chemical polymerization initiator are anticipated to be useful alternative methods. The polymer is then ground to form beads which have a plurality of exposed binding (or receptor) sites for caffeine. The beads are then washed using an acidic alcoholic mixture or other preferred cleaning solution to remove the caffeine molecules from the binding sites on the beads and to provide cavities which function as exposed binding sites that correspond to the molecular imprint (i.e., the shape) of at least a portion of the caffeine molecule. An aqueous solution, such as an extract of a vegetable, for example; a brewed cup of coffee or tea, is exposed to the washed beads. The caffeine molecules randomly align with the vacant receptor sites and are thus bound and removed from the aqueous solution. The aqueous solution is allowed to flow past the beads resulting in a decaffeinated beverage. Adherence of the caffeine molecule to each of the receptor or binding sites occurs through a variety of well-known non-covalent interactions. The use of other known and emergent approaches, including the techniques of sacrificial spacer, copper binding site, and novel covalent approaches, to forming the molecularly imprinted polymers to increase efficacy in aqueous solution are also anticipated. A product in accordance with the principles of the present invention is described that includes an enclosure to contain the MIPS and adapted to permit the aqueous solution to pass through the enclosure and commingle with the MIPS.